Thanks Angelo,
Sorry for the confusion, actually my debug FS has been mounted, i have the folder /sys/kernel/debug
but I don't have the subfolder of "dynamic debug" under the folder /sys/kernel/debug , here is the layout of the debug folder
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ls /sys/kernel/debug/
allocators debug_enabled extfrag mmc1 regulator usb
asoc devfreq fault_around_bytes mmc2 remoteproc v4l2-async
audio_pll_monitor device_component gc opp sleep_time wakeup_sources
bdi devices_deferred gpio phy split_huge_pages
block dma_buf hid pinctrl stmmaceth
bluetooth dma_pools ieee80211 pm_genpd suspend_stats
cec dmaengine iio pwm swiotlb
clk dri memblock regmap ufshcd